What are the causes of retinal phlebitis and arteritis?

Causes of Retinal Phlebitis and Arteritis

Retinal vasculitis encompasses both phlebitis (venous inflammation) and arteritis (arterial inflammation), with infectious causes predominantly affecting arteries while non-infectious systemic diseases more commonly involve veins, though mixed patterns occur. 1, 2, 3

Infectious Etiologies

Viral Causes

• Herpes simplex virus (HSV) produces retinal vasculitis with immunologically mediated infiltrates and is a major infectious cause 1
• Varicella-zoster virus (VZV) causes retinal vascular inflammation with high-quality evidence supporting this association 1
• Cytomegalovirus (CMV) is an important cause of infectious retinitis and retinal vasculitis, particularly in immunocompromised patients 4
• Epstein-Barr virus may produce retinal vasculitis, though with lower-level evidence 1

Parasitic Causes

• Toxoplasma gondii represents the most common parasitic cause of retinal vasculitis, producing retinochoroiditis and is the most common infectious cause of retinitis overall 4, 1
• Onchocerca (nematode) may cause retinal vascular inflammation with moderate-level evidence 1
• Toxocara species, Echinococcus species, and Onchocerca volvulus can involve the uvea and retina in cases of trauma or severe immunosuppression 4

Bacterial Causes

• Mycobacterium tuberculosis is an important bacterial cause of uveitis/retinitis 4
• Treponema pallidum (syphilis) causes infectious retinal vasculitis 4

Key Clinical Distinction

Infectious vasculitis characteristically exhibits arterial involvement (arteritis in 57.9% of infectious cases versus 11.2% in non-infectious), with inflammatory artery sheathing (33.7% versus 0%), artery occlusion (22.1% versus 3.7%), and ischemic areas being strongly suggestive of infectious etiology. 3

Non-Infectious Systemic Etiologies

Systemic Vasculitides

• Giant cell arteritis (GCA) represents an ophthalmologic emergency that must be excluded promptly in patients over 50, as it causes central retinal artery occlusion with retinal vascular inflammation through inflammatory disease of the proximal ocular artery 1, 2, 5
• Granulomatosis with polyangiitis (Wegener's) produces retinal vasculitis as part of systemic manifestations 1
• Polyarteritis nodosa causes inflammatory retinal vessel involvement 1
• Eosinophilic granulomatosis with polyangiitis (Churg-Strauss syndrome) is associated with retinal vasculitis 1
• Microscopic polyangiitis can manifest with retinal vascular inflammation 1
• Kawasaki disease (primarily affecting children) may involve retinal vessels 1

Autoimmune/Connective Tissue Diseases

• Systemic lupus erythematosus (SLE) is a well-established cause with arterial or mixed arteriovenous vasculitis, showing a 3.5-fold increased incidence of retinal vascular occlusions and characteristically producing microinfarctions, cotton wool spots (38.3%), and retinal hemorrhages (34%) 1, 2, 6, 7
• Sarcoidosis represents a major systemic inflammatory condition commonly presenting with venous involvement and may be associated with branch retinal vein occlusion 1, 2, 6
• Behçet's disease shows strong association with posterior segment involvement, predominantly affecting veins, with the primary pathology being vessel wall inflammation rather than thrombophilia 5, 6
• Rheumatoid arthritis can be associated with retinal vascular inflammation 1
• Relapsing polychondritis may produce retinal vasculitis 1
• Multiple sclerosis is associated with retinal vasculitis, with periphlebitis occurring in 25.1% and venous occlusion/thrombosis in 43.75% of cases 6, 7

Drug-Induced Causes

Methamphetamine, intravenous immunoglobulins, opioids, hydralazine, antifibrotics, antibiotics, and leukotrienes can all cause drug-induced vasculitis affecting retinal vessels 1

Vascular Compartment Patterns

Arterial Predominance

• Giant cell arteritis is the most common arteritic cause, affecting medium and large extracranial arteries with occlusive intimal hyperplasia 2
• Infectious etiologies predominantly show arterial involvement with inflammatory sheathing and occlusion 3

Venous Predominance

• Sarcoidosis commonly presents with venous involvement 2
• Behçet's disease predominantly affects veins 6
• Retinal phlebitis may be associated with branch retinal vein occlusion, though it is critical to distinguish true inflammatory phlebitis from thrombotic/embolic retinal vein occlusions 2

Mixed Arteriovenous Pattern

• Systemic lupus erythematosus frequently shows mixed arterial and venous involvement 2, 6
• In more than half of primary retinal vasculitis cases (58.8%), both arteries and veins are involved in the inflammatory process 7

Critical Clinical Pitfalls

In patients over 50 years with retinal arteritis, giant cell arteritis constitutes an ophthalmologic emergency requiring immediate high-dose corticosteroid treatment to prevent vision loss in the fellow eye. 5 The condition causes simultaneous ischemia of inner and outer retina plus optic disc through vessel wall thickening and occlusion 5

Findings of vasculitis and occlusion, especially in retinal arteries on fluorescein angiography, strongly suggest an infectious origin of active uveitis and should prompt appropriate antimicrobial workup rather than immunosuppression alone. 3